The present invention relates to a converter for sophisticated requirements, having low-inductance capacitors in an intermediate-circuit assembly.
Converters of high power density are sufficiently known in the prior art. In DE 41 10 339 C2, a DC/AC converter with DC leads is characterized by several smoothing capacitors connected in series and in close proximity to at least one DC lead. The DC leads were designed in the form of plates. The arrangement of the discretely designed capacitors in relation to the intermediate circuit and the circuit parts of the converter is shown in the figures and described in the text of DE 41 10 339 C2.
DE 42 32 763 C2 suggests that a converter can be made by using multilayer connector buses, describing their low-inductance positioning. In that solution, too, the starting point is the use of discretely arranged capacitors.
An even better defined position of the outer ports of discrete capacitors, related to the above, is described in DE 196 19 538 A1. Furthermore, to realize a converter arrangement with the lowest possible inductance, several suggestions are made for the circuitry of the DC-carrying circuit portions.
In summary, conventional power electronics systems use various individual components to form a complete converter. In power electronics, the design of the switches causes the greatest loss. For that reason, the switches are mounted on a cooling system.
In more recent versions of converters, the drive is integrated into the design of the power electronics and is contacted by means of solder pins flush with the power portion, or electrically, by means of positive connections. The intermediate circuit is provided with electrolytic or foil capacitors. The intermediate-circuit bus is advantageously of low inductance and in sandwich form, while the connection to the power electronics is accomplished by means of a detachable screw connection.
Screw connections as well as soldered connections create additional inductance in the commutation circuits, thereby limiting the maximum possible intermediate-circuit voltage. Furthermore, space and access must be provided for the screw connections, which defeats the purpose of a compact design of high component density.